1. Field of the Invention
The present invention relates to a portable radio apparatus for transmitting and receiving a signal to and from a base station in a communication service area.
2. Description of the Related Art
Usually, a portable radio apparatus can communicate with a desired destination only when it is within an area where it can receive radio data from a base station of communication services, or a communication service area. Outside the communication service area, the portable radio apparatus cannot communicate with the desired destination. For the reason, a conventional portable radio apparatus, for example, an electronic organizer incorporating a radio modem, continuously displays on its display area information indicating whether or not the portable radio apparatus is within a communication service area to prevent its user located outside a communication service area from repeating an transmitting operation. In this manner, the user ascertains that his or her portable radio apparatus is located within a communication service area from content of the display area before transmission of data. Thus, such electronic organizer can reduce unnecessary transmitting operation by the user outside the communication service area.
However, in such portable radio apparatus, even if the user performs an operation for transmitting data outside a communication service area, he or she cannot transmit data until the portable radio apparatus enters into a communication service area. Therefore, the user should wait to transmit data until the portable radio apparatus enters into the communication service area. Alternatively, the user should return in communication service area as soon as possible. In addition, to transmit data to a desired destination, the user should ascertain that the portable radio apparatus is in a communication service area by purposely viewing the display area before he or she performs a transmission operation.
Japanese laid-open patent application heisei 6-224838 discloses a mobile telephone set in which the mobile telephone set determines whether it exists within a service area, and stores in a memory a phone number of a destination which is inputted while the telephone was located outside the service area. When the mobile telephone set enters into a service area, it automatically transmits the phone number stored in the memory, and connects a line with the destination for call.
Japanese laid-open patent application heisei 4-238421 discloses an automatic re-originating system which, when a mobile station moves outside a service area and becomes incapable of receiving data from a base station, the base station stores such data together with the phone number of the mobile station therein. When the mobile station returns to the service area, the base station automatically sends the stored data to the mobile station based on a calling signal from the mobile station in the service area.
Japanese laid-open patent application heisei 5-183624 discloses a radio telephone set in which, when an originating call arrives at a parent telephone set from a base station, the parent telephone set determines whether or not a child telephone set is located outside a radio wave coverage. When the parent telephone set determines that the child telephone set is located outside the radio wave coverage from the parent telephone set, that is, when a call cannot be established between the parent and the child telephone sets, the parent telephone set temporarily stores the message. When the child telephone set returns within the radio wave coverage from the parent telephone set, the parent telephone set sends the message to the child telephone set.
All of the foregoing systems send temporarily stored data to an applicable destination mobile station in the order that they were stored. Thus, if a plurality of data for the same destination mobile station are stored, the plurality of data should be individually sent to the same destination mobile station, Therefore, the number of transmission and receiving of data increases, so that the communication line cannot be efficiently used.
The mobile telephone set disclosed in Japanese laid-open patent application heisei 6-224838 in particular increases the number of transmission of the stored data, leading to increase of battery consumption. Therefore, the working time is shortened for the mobile station.
In addition, if the number of phone numbers and messages being stored increases, it is difficult to apply such conventional technologies to a portable radio apparatus with limited amount of memories which can be provided for the apparatus. In addition, it is necessary to previously provide a large capacity of memory for a portable radio apparatus not limited for the amount of memory which can be mounted. Therefore, the size of the apparatus itself cannot be reduced.